Spin-orbit-coupled Bose-Einstein-condensed atoms confined in annular potentials

TL;DR

This paper explores the diverse phases of spin-orbit-coupled Bose-Einstein condensates confined in annular traps, revealing how interactions and geometry influence density patterns and circulation states.

Contribution

It provides a detailed analysis of phase transitions and novel circulation solutions in spin-orbit-coupled BECs within annular potentials, extending understanding beyond non-interacting models.

Findings

Homogeneous phase replaced by sinusoidal density in narrow annuli

Presence of striped-like density phase in untrapped systems and narrow annuli

Interactions determine the stability of striped, homogeneous, or sinusoidal phases and induce nonzero circulation solutions

Abstract

A spin-orbit-coupled Bose-Einstein-condensed cloud of atoms confined in an annular trapping potential shows a variety of phases that we investigate in the present study. Starting with the non-interacting problem, the homogeneous phase that is present in an untrapped system is replaced by a sinusoidal density variation in the limit of a very narrow annulus. In the case of an untrapped system there is another phase with a striped-like density distribution, and its counterpart is also found in the limit of a very narrow annulus. As the width of the annulus increases, this picture persists qualitatively. Depending on the relative strength between the inter- and the intra-components, interactions either favor the striped phase, or suppress it, in which case either a homogeneous, or a sinusoidal-like phase appears. Interactions also give rise to novel solutions with a nonzero circulation.